matheygroup.bsky.social @matheygroup.bsky.social · 19/09/2026Quantum liquids continue to display mind-bending phenomena, here we propose to create memory effects in a condensate: arxiv.org/abs/2609.19260 , specifically hysteretic dynamics across a Josephson junction, with Vijay and Luigi. 010
matheygroup.bsky.social @matheygroup.bsky.social · 25/08/2026Deep dive into the relation of quantum dynamics and non-linear dynamics: arxiv.org/abs/2605.24122 . Using a hidden Markov model, we watch the quantum system escape from one limit cycle to another. It's quantum escape, expanding the idea of quantum jumps, explored with Caro and Kilian! 000
matheygroup.bsky.social @matheygroup.bsky.social · 17/08/2026Controlling quantum dynamics via circuits, as a new way to design Hamiltonians on demand : arxiv.org/abs/2606.17158 . We point out how to taylor quantum dynamics with a sequence of quantum gates and free evolution, avoiding Floquet heating. Many thanks to Özgün and Martin! 010
matheygroup.bsky.social @matheygroup.bsky.social · 13/08/2026Optimal control of quantum dynamics aims to implement quantum algorithms in realistic systems. Our new algorithm arxiv.org/abs/2607.24725 navigates the fidelity landscape efficiently. Instead of taking steps up the hill, jump to the top! It's gradient- and hyperparameter-free. Many thanks to Lia! 000
matheygroup.bsky.social @matheygroup.bsky.social · 08/07/2026Quantum liquids display quantum behavior on macroscopic scales, such as quantized vortices. In www.pnas.org/doi/10.1073/... we demonstrate how to make quantized vortices on-demand. It's been a great collaboration with Vijay as the lead author, and with Herwig and Luigi! 000
matheygroup.bsky.social @matheygroup.bsky.social · 13/06/2026Here is our tutorial-like retrospective of time crystals, a form of quantum matter in motion: arxiv.org/abs/2605.23881 It's been a fun ride, written with Jayson, on our long-time collaboration with Andreas and his team. Time crystals, three ways, enjoy! 000
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 23/03/2026📣New publication on "Atomic Josephson parametric amplifier" by CUI member Prof. Ludwig Mathey et al. @matheygroup.bsky.social 👉https://journals.aps.org/prresearch/abstract/10.1103/7s1n-ddp9 @uni-hamburg.de @apsphysics.bsky.social 001
matheygroup.bsky.social @matheygroup.bsky.social · 11/03/2026Superconductivity continues to be a focal point of research, from fundamentals to technology and qubits. The U(1) lattice gauge system is one of these iconic models, here is our take on the phase transition: arxiv.org/abs/2603.09895 , where we clarified the critical behavior. Great work, Greta! 000
matheygroup.bsky.social @matheygroup.bsky.social · 05/03/2026To develop quantum technologies we need new numerical methods, here is our latest: arxiv.org/abs/2603.04066 . It uses quantum jumps in the quantum technology-relevant regime, nicely developed by Marcus. You can pair it with any quantum dynamics method out there, get in touch if you'd like to try. 000
matheygroup.bsky.social @matheygroup.bsky.social · 04/03/2026How to make a topological superfluid in a driven cavity, and get a first-order phase transition in the process: arxiv.org/abs/2603.03034 . It's been fun figuring this out with Hannah, thanks to her work and dedication! 000
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 08/01/2026📣New publication on "Realizing an atomic quantum interference device in a rotating-box potential" by CUI member L. Mathey @physrevlett.bsky.social @uni-hamburg.de journals.aps.org/prresearch/a...journals.aps.orgRealizing an atomic quantum interference device in a rotating-box potentialAtomtronic devices are matter-wave circuits designed to emulate the functional behavior of their electronic counterparts. Motivated by superconducting quantum interference devices (SQUIDs), atomic qua... 031
Reposted by @matheygroup.bsky.socialScience X / Phys.org @sciencex.bsky.social · 12/12/2025Quantum simulation using Bose-Einstein condensates has replicated Shapiro steps, demonstrating that this key quantum effect can be observed in atomic systems as well as superconducting junctions. doi.org/hbfhvmphys.orgAtomic Josephson contacts: How Bose-Einstein condensates replicate Shapiro stepsThe microscopic processes taking place in superconductors are difficult to observe directly. Researchers at the RPTU University of Kaiserslautern-Landau have therefore implemented a quantum simulation of the Josephson effect: They separated two Bose-Einstein condensates (BECs) by means of an extremely thin optical barrier. 011
matheygroup.bsky.social @matheygroup.bsky.social · 12/12/2025Excited to have our study on Shapiro steps out: Observation of Shapiro steps in an ultracold atomic Josephson junction | Science www.science.org/doi/10.1126/...science.orgObservation of Shapiro steps in an ultracold atomic Josephson junctionThe current-voltage characteristic of a driven superconducting Josephson junction displays discrete steps. This phenomenon, called the Shapiro steps, forms today’s voltage standard. In this work, we r... 000
matheygroup.bsky.social @matheygroup.bsky.social · 15/11/2025Designing material properties by putting them into a cavity is promising route of material design. Recent study with Hector on cavity control of Raman-active matter: arxiv.org/abs/2511.08586 000
matheygroup.bsky.social @matheygroup.bsky.social · 15/11/2025Making vortex rings in a condensate, via Shapiro dynamics: arxiv.org/abs/2511.05645 , joint study with Vijay, Luigi, and Herwig. Looks a little like smoke rings! 000
matheygroup.bsky.social @matheygroup.bsky.social · 14/11/2025Dial up the tunneling, between two Bose-Einstein condensates, and see the phases order! Recently demonstrated in collaboration with Chris' team and Vijay, here: arxiv.org/abs/2510.23600 000
matheygroup.bsky.social @matheygroup.bsky.social · 16/10/2025A new platform to push next-gen electronics towards quantum coherence, patterned graphene nanoribbons: arxiv.org/abs/2510.08678 . Patterned electrodes provide control of the band structure to enable coherent electronics. Riek and Hector, this was fun! 010
matheygroup.bsky.social @matheygroup.bsky.social · 07/10/2025Tunneling is one of these quintessential, unintuitive quantum phenomena: particles overcoming barriers that they don't have the energy for, from a classical perspective. With Herwig and his team, and with Vijay and Luigi, we took a closer look, see here: arxiv.org/abs/2509.03591 010
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 04/09/2025📣New publication by CUI member L. Mathey et al. on "Observation of a bilayer superfluid with interlayer coherence" www.nature.com/articles/s41... @matheygroup.bsky.social @natcomms.nature.comnature.comObservation of a bilayer superfluid with interlayer coherence - Nature CommunicationsThe authors report the implementation of a bilayer system of 2D ultracold Bose gases with controllable Josephson coupling. This allows characterisation of coupling-induced superfluid phases and their ... 041
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 27/05/2025Wir freuen uns auch riesig, weitere 7 Jahre exzellente Forschung betreiben zu dürfen! 021
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 05/06/2025📢New publication on "Torus Bifurcation of a Dissipative Time Crystal" by CUI members L. Mathey and A. Hemmerichet al. 👉https://uhh.de/jq9iz23601 @physrevlett.bsky.social @uni-konstanz.de 021
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 07/07/2025📢New publication on "Non-linear photoconductivity of strongly driven graphene" by CUI member Ludwig Mathey and Lukas Broers scipost.org/SciPostPhys.... #SciPost #graphenescipost.orgSciPost: SciPost Phys. 18, 199 (2025) - Non-linear photoconductivity of strongly driven grapheneSciPost Journals Publication Detail SciPost Phys. 18, 199 (2025) Non-linear photoconductivity of strongly driven graphene 021
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 24/07/2025📣New publication on "Hybridization of the amplitude mode in a confined fermionic superfluid" by CUI members C. R. Cabrera, L. Mathey, H. Moritz et al. @apsphysics.bsky.social @dfg.de journals.aps.org/prresearch/a...journals.aps.orgHybridization of the amplitude mode in a confined fermionic superfluidThis work reveals how confinement affects fundamental excitations in a fermionic superfluid. In particular, the hybridization of the amplitude mode with a spatial breathing mode of the condensed part ... 021
matheygroup.bsky.social @matheygroup.bsky.social · 28/08/2025Atomtronics is the scientific endeavor of building circuits out of quantum liquids. Here, we give the field a new twist, via rotating-box potentials: arxiv.org/abs/2508.17889 Thanks to Kaspar and Vijay, for making this fun project a reality! 010
matheygroup.bsky.social @matheygroup.bsky.social · 08/07/2025Like ice in the sunshine, a limit torus melts away due to quantum fluctuations: arxiv.org/abs/2507.03764 Big thanks to Caro and Kilian! 010
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 22/05/2025🎉Here's to another seven years!! Great success for the Center of Excellence CUI: From 1 January 2026, the Cluster of Excellence “CUI: Advanced Imaging of Matter” will be funded for a further seven years! @uni-hamburg.de @europeanxfel.bsky.social #mpsdhamburg #desy 071
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 14/05/2025📣New publication on "Detecting Phase Coherence of 2D Bose Gases via Noise Correlations" by i.a. CUI member L. Mathey @uni-hamburg.de @apsphysics.bsky.social doi.org/10.1103/Phys...doi.orgDetecting Phase Coherence of 2D Bose Gases via Noise CorrelationsWe measure the noise correlations of two-dimensional (2D) Bose gases after free expansion and use them to characterize the in situ phase coherence across the Berezinskii-Kosterlitz-Thouless (BKT) tran... 021
matheygroup.bsky.social @matheygroup.bsky.social · 25/04/2025Looking forward to our upcoming workshop on Rydberg physics, organized by Aslam, Rohan, and Zeki! www.physik.uni-hamburg.de/en/iqp/schme... 000
matheygroup.bsky.social @matheygroup.bsky.social · 31/03/2025Atomtronics is the field of building logical circuits out of cold atoms. Here is our newest circuit element, the Josephson parametric amplifier: arxiv.org/abs/2503.20890 Fun collaboration with Vijay and Luigi! 000
Reposted by @matheygroup.bsky.socialCUI: Advanced Imaging of Matter @cui-unihh.bsky.social · 17/03/2025📢New publication on "Coherent control of photoconductivity in graphene nanoribbons" by CUI member L. Mathey, H. P. Ojeda Collado and L. Broers journals.aps.org/prb/abstract... @networkspapers.bsky.social @unihhjournals.aps.org 021
matheygroup.bsky.social @matheygroup.bsky.social · 18/03/2025Oh, snap, it's a preprint, on our proposal for a quantum gate, the eigen-SNAP gate: arxiv.org/abs/2503.09292 Photonic states in cavities are used as qubits, two-qubit gates are mediated via a transmon. Nice job, Marcus! 000
matheygroup.bsky.social @matheygroup.bsky.social · 11/03/2025Excited to announce the IQP Seminar series for the upcoming semester. Looking forward to these visits! 000
matheygroup.bsky.social @matheygroup.bsky.social · 10/03/2025Just published in PRB: Coherent control of photoconductivity in graphene nanoribbons journals.aps.org/prb/abstract... Thanks for this interesting collaboration, Hector and Lukas!journals.aps.orgCoherent control of photoconductivity in graphene nanoribbonsWe study the photoconductivity response of graphene nanoribbons with armchair edges in the presence of dissipation using a Lindblad--von Neumann master equation formalism. We propose to control the tr... 000
matheygroup.bsky.social @matheygroup.bsky.social · 05/02/2025Upcoming workshop on Rydberg physics at the ZOQ: www.physik.uni-hamburg.de/en/iqp/schme... . Jointly organized with Peter Schmelcher, who I have the pleasure of being colleagues with. From my team, Aslam is doing a great job at the heavy lifting, together with Zeki and Rohan, thanks to all of you!physik.uni-hamburg.deCUI Young researchers workshop FORM 2025 000
matheygroup.bsky.social @matheygroup.bsky.social · 27/01/2025Our paper on PEPR just came out! It's method for quantum optimization, based on projecting response functions: journals.aps.org/prresearch/a... It was fun to come up with this, and try it out! 000
matheygroup.bsky.social @matheygroup.bsky.social · 19/01/2025Fascinating preprint by the group of Jian-Wei Pan on the counterflow SF state in a bosonic mixture arxiv.org/abs/2403.03479 . We discussed this in journals.aps.org/pra/abstract... , with Anzi, Eite, Ippei, Carl and Charles, and the noise signature here: journals.aps.org/pra/abstract...arxiv.orgObservation of counterflow superfluidity in a two-component Mott insulatorThe counterflow superfluidity (CSF) was predicted two decades ago. Counterintuitively, while both components in the CSF have fluidity, their correlated counterflow currents cancel out leading the over... 000
matheygroup.bsky.social @matheygroup.bsky.social · 25/11/2024I have received some questions about the picture I posted. Is it a Minecraft monster? Is it a Pokemon..? It is actually the snapshot of a condensate simulation, subjected to environments that make it form wires and transistors, enabling circuits based on superfluidity. 000
matheygroup.bsky.social @matheygroup.bsky.social · 22/11/2024New preprint on designing atomtronic circuits: arxiv.org/abs/2411.13642 . We are using superfluid dynamics to build AND, NAND and NOT gates. Many thanks to Sarah and Vijay for this collaboration! 010
